1. Field of the Invention
The present invention relates to a developing device and an image forming apparatus and particularly to a developing device equipped with a toner carrier to supply toner to an electrostatic latent image of an image carrier as well as an image forming apparatus equipped with this developing device.
2. Description of the Related Art
A developing device equipped with a toner carrier to supply toner to the electrostatic latent image of an image carrier has been known. See, for example, Japanese Patent Application Laid-Open Publication No. 2000-147889.
Japanese Patent Application Laid-Open Publication No. 2000-147889 discloses a developing device equipped with a photoreceptor on which the electrostatic latent image is formed, a developing roller for supplying toner to the electrostatic latent image of the photoreceptor, and a cleaning device for recovering toner adhering to the photoreceptor. This developing device is provided with a toner forced consumption mode by which, after it is determined that toner replenishment is required, the remaining toner is forcibly consumed. With this toner forced consumption mode, the constitution is such that the electrostatic latent image is forcibly formed on the photoreceptor, and the remaining toner is consumed by having the toner forcibly supplied to the electrostatic latent image of the photoreceptor via the developing roller. Then, the toner supplied to the photoreceptor is recovered by the cleaning device.
However, the developing device of Japanese Patent Application Laid-Open Publication No. 2000-147889 is constituted such that the electrostatic latent image is forcibly formed on the photoreceptor, and the remaining toner is forcibly supplied to the electrostatic latent image of the photoreceptor. Therefore, despite being unrelated to the printing operation, the electrostatic latent image is formed on the photoreceptor, and toner adheres to the photoreceptor, so there is a problem in that degradation of the photoreceptor is correspondingly faster.